Knee braces are widely used to treat a variety of knee infirmities. Such braces may be configured to impart forces or leverage on the limbs surrounding the knee joint to relieve compressive forces within a portion of the knee joint, or to reduce the load on that portion of the knee. In the event that knee ligaments are weak and infirm, a knee brace may stabilize, protect, support, unload, and/or rehabilitate the knee.
The knee is acknowledged as one of the weakest joints in the body, and serves as the articulating joint between the thigh and calf muscle groups. The knee is held together primarily by small but powerful ligaments. Knee instability arising out of cartilage damage, ligament strain and other causes is relatively commonplace since the knee joint is subjected to significant loads during the course of almost any kind of physical activity requiring using the legs.
A healthy knee has an even distribution of pressure in both the medial and lateral compartments of the knee. It is normal for a person with a healthy knee to place a varus moment on the knee when standing so the pressure between the medial and lateral compartments is uneven but still natural.
One type of knee infirmity that many individuals are prone to having is compartmental osteoarthritis. Compartmental osteoarthritis may arise when there is a persistent uneven distribution of pressure in one of the medial and lateral compartments of the knee. Compartmental osteoarthritis can be caused by injury, obesity, misalignment of the knee, or due to aging of the knee.
A major problem resulting from osteoarthritis of the knee is that the smooth cartilage lining the inside of the knee wears away. This leads to a narrowing of the joint space with developing cysts and erosions in the bone ends. Because of the narrowing of the joint, bone comes directly in contact with bone, and an uneven distribution of pressure develops across the knee which may cause the formation of bone spurs around the joint. All of these changes ultimately lead to increasing pain and stiffness of the joint.
While there are no cures to osteoarthritis, there are many treatments. Individuals who have diagnosis of isolated medial or lateral compartmental osteoarthritis of the knee are confronted with a variety of treatment options such as medications, surgery, and nonsurgical interventions. Nonsurgical interventions include using canes, lateral shoe wedges, and knee bracing.
Knee bracing is useful to provide compartmental pain relief by reducing the load on the affected compartment through applying an opposing external valgus or varus moment about the knee joint. Unloading knee braces have been shown to significantly reduce osteoarthritis knee pain while improving knee function.
In these unloading braces, straps fasten the brace to the limb and enable the strap to exert forces on the knee to unload the affected compartment of the knee. The tension in a strap affects the function, fit and comfort of the brace, especially when the strap is used to unload the knee. Inadequate tension may diminish the effectiveness of the brace to not only unload the knee but to stabilize the brace as well, whereas excessive tension may cause discomfort to the wearer. It would be beneficial to provide a device that indicates how much tension is in a strap and provide means by which the tension of the strap can be easily controlled.
The prior art suffers from disadvantages of providing adequate means for identifying the tension level or tightening in a strap, and rarely allows for incremental tensioning control of the strap at a plurality of predefined settings.